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4.2. Fenalenilnyj a radical as a part of heavy resin of pyrolysis iosobennosti technogenic asphaltenes


On installations of pyrolysis of an oilstock along with main products - unsaturated compounds (С2-Сз) in the ratio to 1:1 on weight form liquid fraction (pyrolysis resin), containing mono - bi - and polycyclic aromatic hydrocarbons and them alkilproizvodnye.
Aromatic hydrocarbons are products of the secondary reactions and are formed from alkenovyh connections.
Through a diene synthesis there is a transformation of aromatic, nonlimiting monocyclic and acyclic connections. And then, in dehydrocondensation processes - formation of polycyclic aromatic compounds. Nonequilibrium condition thermodynes-cheskie in plant operation (the heat and sharp quenching) result in to very wide spectrum of formed chemical combinations, including labile and paramagnetic.
It is possible to present the general schema of passing of reaction in a kind:
Alkanes-> Alkenes—> Arenas—> the Condensed arenas
Chromatographic research of [114] mixes of liquid resultants of reaction has shown presence of benzol, toluene, xylene, alkilbenzolov Сд-С9, naphthalene, alkilnaftalinov, indenes, diphenyl, acenaphthene, fluorene, fe - nantrena, anthracene, tetralins, and them metilproizvodnyh. Besides, at the specified mix there are acyclic and alicyclic dienes, vinyl - romaticheskie connections, paraffin and naphthenes.
One of interesting connections, from the point of view of industrial chemistry acenaphthene, as a rule, evolved of anthracene fraction of coal tar is. Acenaphthene dehydrogenation result ins to formation of acenaphthylene which is used for reception of dyes, anti - oxidizers etc. Heavy resin of pyrolysis in Open Society "Нижнекамскнефтехим" use for carbon reception.
The method of an electronic paramagnetic resonance is applied to identification of series of compounds as a part of TSP Open Society "Нижнекамскнефтехим" [115].
In EPR spectrum TSP there is a line with g-factor size g=2.0030 and width DN = 6-8 ersted (), characteristic for the majority of products of degradation of organic matters (neftej and mineral oil, coal tar, peat extracts), including thermal degradation. The line is not decomposeed owing to a huge variety of the included paramagnetic products. However in EPR a spectrum deasfaltizata TSP (fig. 21) on the basic line overlaps malointensivnyj a spectrum of individual paramagnetic connection with g = 2.0026 and with hyperfine interaction from 6 protons with a constant of hyperfine interaction (STV) avi = 6.29 e and from 3 protons with constant STV azn = 1.87 e. Similar
The spectrum coincides with a spectrum fenalenilnogo a radical easily received at oxidation by oxygen of air of individual connection fsna - lenila [116, 117].

Fenalenilnyj a radical (fig. 22а) in a range 293 — 393 To is in balance with the diamagnetic dimer form. At depressing by that-peratury the spectrum is reversible disappears. Heating in anaerobic conditions and long-term storage deasfaltizata TSP also depresses signal strength. Stabilisation by surrounding connections with formation of supermolecular structures and high symmetry fenalenilnogo a radical, result ining fixings in spectrum EPR only two grades of protons, promotes its detection in a mix.
Monosubstitution in fenalenilnyj a radical will lead to asymmetry of interaction of protons with not coupled electron, to sensitivity loss, and not resolved hyperfine structure in spectrum EPR will lead to fixing of only wide single line. Symmetry depressing can lead also to increase of enthalpy of dissociation of dimer or to depressing of concentration of the paramagnetic form at the yielded temperature. 1 2

And
Fig. 22.
And - fenalenilnyj a radical; — acenaphthylene Fixing of spectrums EPR of individual connections has encouraged us on search of other individual products as a part of TSP. Oxidation deas - faltizata TSP lead dioxyde (РЬ02), i.e. homolytic breakoff of a mobile proton result ins fixings of spectrum EPR (fig. 23) from paramagnetic concerning a steady product, with g = 2.0042 and constant STV caused by splitting from 3 protons а3ц=11.3 e and 2 protons agn=1-7 e. Moderately big constant STV from 3 protons specifies in presence СНз-С*< - фрагмента в молекуле, сопряженного с ароматическим фрагментом. Сдвиг g-фактора в низкие поля обусловлен, вероятно, присутствием гетероатомов в молекуле радикала.

I 1!
1 7.!
M I
71 (>
і І І
: і (І d
І І 1
V. і
Fig. 23. Lead
Spectrum EPR deasfaltizata TSP after oxidation by dioxide
¦. •
Electrolysis deasfaltizata TSP it is direct in the resonator of spectrometer EPR in the presence of 50 % on volume basis dimethylformamide and background salt Et4NC104 (With = 0.1 mole/l) in a temperature range 213 - 253 To result ins fixings of intensive spectrum EPR with g = 2.0026 and constant STV а2ц = 5.67 e; а2н = 4.58 e; agn = 3.06 e; а2н = 0.48 e (fig. 24), acenaphthylene unequivocally attributed to an anion-radical [118]. Formation anion of radicals at electrochemical restoration of the condensed aromatic compounds well-known. The fixing fact mainly one type of radicals is surprising. That, obviously, it is connected with rather high concentration of acenaphthylene (fig. 226) in a mix and low potential of its restoration. Products of restoration of other condensed aromatic compounds, possibly, become mediatorami for acenaphthylene restoration, being spent thus.

Thus, method EPR as a part of TSP directly had been identified fenalenilnyj a radical and an indirect route of electrochemical generation acenaphthylene.
Presence as a part of TSP feialenilnogo a radical is possibly connected with its stabilisation in the studied technogenic system, and confirms made before the assumption of similarity of the organisation of technogenic and oil systems. Viscosity decrease neftej with the additive of the hydrocarbonaceous rests of petrochemical processes, possibly, is connected with presence at the rests of labile connections similar fenalenilnomu to a radical.


Fig. 25. IK the Fourier spectrums of technogenic asphaltenes: () - PABS, () - TSP and typical IK the Fourier a spectrum of oil asphaltenes: () - oil asphaltenes (the Matrosovsky deposit, hard currency. № 156)
Besides identification of individual connections as a part of TSP analysis IK the Fourier of spectrums of asphaltenes evolved of TSP and PABS [119] (fig. 25) is carried out.
As raw materials for ethyl benzene synthesis benzol and ethylene, therefore complexity of structure of the asphaltenes received from individual substances serve, should be low. Besides, the raw materials practically do not contain getero nuclear connections and process proceeds short time, that also affects composition of high-molecular components. The less than functional groups in structure of asphaltenes, the more accurately corresponding lines on IK a spectrum. For the specified reasons asphaltenes PABS are characterised bolshej by intensity of absorption bands corresponding metalnym (2955-2965 sm-1), and aromatic (1595-1605 sm-1) to fragments, in comparison with oil asphaltenes.
Practically petrol fractions are exposed to pyrolysis. Process proceeds some seconds. Pyrolysis main products are ethylene and propylene. However the scale of various connections at which sharp quenching the set of the aromatic and condensed structures is synthesised is formed. Hence, asphaltenes TSP should have more difficult composition in comparison with asphaltenes PABS. And in structure of asphaltenes TSP fragments of the aromatic nature should dominate. The last proves to be true IK spectrums. Asphaltenes TSP are characterised by the big maintenance aromatic (3025-3045, 1505-1605 sm-1) and mono - di - and three - substituted aromatic (860-870, 830, 760, sm-1) structures, in comparison with asphaltenes neftej.
Attracts attention presence in spectrums of asphaltenes TSP and PABS intensive absorption band at 1030-1050 sm "1 (fig. 25) attributed by many researchers to fluctuations sulfoksidnoj groups. Definition of the maintenance of sulphur in asphaltenes TSP and PABS a method of double burning has shown full absence of sulphur in the specified objects. The available contradiction specifies in unreliability of estimations of the maintenance sul - foksidov in asphaltenes on intensity of discussed absorption band. Most likely, the significant contribution to intensity of a strip at 1030-1050 sm" ' (at least, for asphaltenes TSP and PABS) bring bitsikloaroma - ticheskie structures [120].
Despite visible distinction in IK spectrums of technogenic and oil asphaltenes, and as distinction in their chemical composition (technogenic the expert-falteny do not contain sulphur - nitrogen - and organometallic compounds in the composition). It is possible to ascertain confidently presence in structure of technogenic asphaltenes of the condensed aromatic system containing more than three benzene rings. Maintenance CP in asphaltenes PABS and TSP
IQ
Makes 101 and 15 (THAT otn.sp./g), accordingly. Possibly, fragments of structure of the investigated technogenic asphaltenes, containing nesparen - nyj an electron, are similar to similar sites of oil asphaltenes. Absence in structure of asphaltenes TSP and PABS connections of paramagnetic vanadium does these objects attractive as models CP for studying of degree of possible interaction VK and COMPARE Studying of this question - a step to an explanation of the nature of existing dependences of the maintenance of free stable radicals from the maintenance vanadilovyh complexes in neftjah and asphaltenes.
Thus, by results of the yielded chapter it is possible to draw following basic conclusions:
The investigated systems of a technogenic origin and oil systems, differing on genesis, have similar macrocharacteristics (density, viscosity), componental composition, the maintenance of free stable radicals and the similar organisation of micelle structures,
For the first time as a part of heavy resin of pyrolysis fenalenilnyj a radical and an indirect route of electrochemical generation acenaphthylene directly is identified.
It is revealed, that in aspect of studying of degree of possible interaction VK and CP as the modelling asphaltenes characterised by presence CP and absence of connections of paramagnetic vanadium, it is possible to use asphaltenes of the rests of processes, pyrolysis and ethyl benzene synthesis.
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A source: Tagirzjanov, Marseilles Ilgisovich. ASPHALTENES VANADIJSODERZHASHCHIH neftej (on an example of oil objects of deposits of Tatarstan) the Dissertation on competition of a scientific degree of a Cand.Chem.Sci. Kazan - 2003. 2003

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